Piston expander



@cfi. 9, 11934.

J. REID 1,975,974

PISTON EXPANDER Filed March 1, 1933 Patented Oct. 9, 1934 retain 4 Glaims.

My invention relates to pistons for internal combustion engines and especially to those made or" aluminum and similar metals and has for its objects to provide means for expanding the skirt of such a piston to prevent its slapping in operation.

My invention can be made of any desired size to the particular make and design of the piston in which it is to be used. The piston itself does not usually have to be altered in any way and does not even have to be removed from the cylinder in order to insert my device and fully correct the fault. In cases where the piston skirt is not split the full length it is necessary to extend the cut in the skirt as far as the T slot under the lowest piston ring, thereby permitting my expander to have full and free action on the skirt.

I attain the above and other objects by the devices illustrated in the accompanying drawing, in which- Fig. 1 is a plan of one form of my improved piston expander before being placed in position in the skirt of a piston; Fig. 2 is an edge view thereof; Fig. 3 is an edge view thereof when bent by means or" a suitable bending pliers in order to insert it in the skirt of a piston to be expanded thereby; Fig. i is a bottom plan view of the piston showing the skirt thereof expanded by one of my improved expanders placed therein; Fig. 5 is an edge View of another form of my invention suitable for a diirerent type of piston than illustrated in Fig. 4; Fig. 6 is a plan view thereof; and Fig. 7 is a View, similar to Fig. 4, showing the expander illustrated in Figs. 5 and 6, in place therein.

Similar numerals of reference refer to similar parts throughout the several views.

The skirt 1 of the piston is slit on one side by a cut 2 extending from its lower edge to the usual T-sict located just below the lower piston ring at the upper end of the piston. This slit 2 is positioned about ninety degrees from the axis of the wrist pin bearing. In the form of ,piston illustrated in Fig. i, the pin bearing bos es 3 are supported by braces 4 extending at right angles to the axis of the pin and connecting directly with the adjacent parts of the skirt 1 a...d with the upper end of the piston. The

above-described slit 2 is, therefore, midway between the two braces 4.

The form of my improved piston expander which is best suited for this particular form of piston, or any piston provided with flat vertical surfaces on each side of the slit, is illustrated in Figs. 1, 2 and 3 and comprises a thin plate 5, of spring steel, having its end edges serrated by teeth 6. These serrations are preferably made complementary to each other, for practical reasons, the spaces between the teeth of one such plate being the teeth of the next plate, thus requiring that one die out only be made for each plate 5.

The above-described expander is applied to the interior of the piston skirt 1, between the two braces 4, by grasping it between the triple jaws of a special pliers. Two or" these jaws 7 (Fig. 3) move together while the central law 8 moves in the opposite direction between the said jaws 7. By applying force to the special pliers, the jaw 8 flexes the plate 5, as shown in Fig. 3. While the plate 5 is thus flexed it is passed upward in the skirt 1 of the piston and is positioned so that, as the jaws 7 and 8 are released by the applying force, its serrated ends contact with the fiat portions or" the braces 4, preferably at a point near the ends thereof adjacent to the slit 2. As the plate 5 straightens out, it forces the skirt sides apart, opening the slit 2 and thus enlarging the skirt and preventing the slap which had developed therein. It is, of course, obvious that the length of the plate 5 between its edges 6 must be slightly greater than the distance between the braces 4 of the piston.

When the piston is or" a design such as is shown in Fig. 7, in which there is no flat brace for either of the bearing bosses against which to place the end of the expander, I have provided the expander plate 11 with two permanent bends 12 adjacent to its serrated ends 13. Usually in a piston of this design there is not as much space for an expander in the skirt and the expander plate 11 is, therefore, narrowerthan the above-described plate 5.

In this case the plate 11 is applied by flexing it in the special pliers, as above described, and inserting it in the skirt 14 in such position that the bends 12 increase the angle that the teeth of the serrated ends 13 would make with the metal of the skirt 1% (Fig. 7), thus enabling the teeth thereof to dig into the metal of the skirt and thus force the slit 15 of the skirt open and therefore correct the fault of the slapping of the piston while in use.

It is, of course, understood that the size of the plate is made to suit the particular piston and that variations therein may be made both in dimensions and the angle or" the bends 12, as required, and without departing from the spirit of my invention as outlined in the accompanying claims.

Having described my invention, what I claim and desire to secure by Letters Patent, is:-

1. A piston skirt expander adapted to be inserted within the skirt of a piston and comprising a flexible spring plate adapted to be removably inserted 'in flexed position within the skirt of the piston without demounting the piston, and to engage the walls thereof with its end edges to press the walls outward by its spring reaction.

2. A piston skirt expander as set forth in claim 1, wherein the end edges which engage the skirt walls are serrated and are thereby adapted to grip the metal of the piston skirt.

3. A piston skirt expander as set forth in claim 1, wherein said plate is normally fiat between its ends, and the end edges are serrated and are thereby adapted to grip the metal of the piston skirt.

4. A piston skirt expander as set forth in claim 1, wherein said plate is normally fiat but is slightly bent adjacent its ends in a direction opposite to the bending of the plate when inserted in the piston skirt, and the end edges thereof are serrated and are thereby adapted to grip the metal of the piston skirt.

JOHN REID. 

